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Area of a Square

Area of a Square - C Programming Example

In this C program example the length of one arm of the square will be given as input. Output will show the area of the square.

Area of a square

C Programming Code

#include<stdio.h>

#include<conio.h>

main()

{

float a,area;

printf("Please enter the length of a side of the square: \n");

scanf("%f",&a);

area=a*a;

printf("The area of the square is %.2f \n",area);

getch();

}

Output example

Area of a square output

Explanation

·#include<stdio.h>

#include<stdio.h>

ØThis are called header file.A header file is a file with extension .h which contains C function declarations and macro definitions to be shared between several source filesThe C programming language provides many standard library functions for file input and output. These functions make up the bulk of the C standard library header<stdio.h>.In the other hand <conio.h> is a C header file used mostly by MS-DOS compilers to provide console input/output. It is not part of the C standard library or ISO C. This header declares several useful library functions for performing "console input and output" from a program.

·main()

ØIn C, program execution starts from the main() function. The main function can in-turn call other functions. When main calls a function, it passes the execution control to that function. The function returns control to main when a return statement is executed or when end of function is reached.

·float a,area;

Øfloat is a variable or data type. A variable declared to be of type float can be used for storing floating-point numbers (values containing decimal places). Here we declare “a” and “area”variable in float type. So this two variable can take values containing decimal number.

·printf() function

ØC uses printf() function to write from the input devices. This function has been declared in the header file called stdio.h . Any text written within the pair of quotes ("") is displayed as such by printf() function on the screen.

·scanf() function

ØThis function is used to get input from the user of the program. scanf(“%f”,&a”) is used here. So, this program will read in a float value for “a” variable that the user enters on the keyboard ( %f is for float values. As there is “&a”, the number user enters will be the value of “a” variable).

·printf("The area of the square is %.2f \n",area);

Ø%.2f is used to print the main result. As “area” variable is declared after the “ ” sign, this will print the value of “area” valuable. “.2f” is used to print only the first 2 digits after the point.

·getch() function

Øgetch() is used to hold the console(output) window on the screen after the whole program run is completed till the user enters a key from keyboard. This function is present in the header file called conio.h.

Final Result

This program will show you the area of a square. What you need to do is, just input the length of one arm of the square.